SAM effects

[Jwg1749]

Frank, do you (or does anyone else) know how the speaker protection in SAM actually works? The point that I find hard to understand is how SAM can measure cone excursion "in real time" (as it claims on the SAM pages). That's to say, how can the DSP in the amp know how far the cone is moving without physically measuring it (which Devialet can do in their labs but is impossible "in real time")?
I could understand if SAM worked predictively, i.e. based on the lab measurements, SAM would be able to predict what SPLs were likely to generate excessive cone excursion and would limit power accordingly. But that's not really "in real time", is it?
Not sure if I've expressed myself clearly.
Matt